Glossary of Terms

Code field

A field that contains reusable code in the form of ioL tags and values, which can be reused each time an event is triggered.

Document

The live, structured content that makes up the interface presented to the user in the console, including the tags and fields that define it, and all content presented to the user, constructed from the program's output.

Document tree

The hierarchy of tags and fields that make up the document. Each tag instance exists within this tree, and fields may contain values, other tags, or code.

Field

A property of a tag that may contain values, tags, or code. Fields are used to define behaviour and structure within a tag.

Generate

Some tags generate a value or values as the result of carrying out an operation. The generated value(s) then become part of the surrounding document or expression. In some cases multiple values may be generated while a tag is being evaluated. For example, a "for" loop generates the contents of the loop repeatedly. Generated values are analogous (but not identical in all cases) to "return values" found in procedural programming languages.

Presentation container field

A field that allows deeper document structure within a presentation container tag.

Presentation container tag

A presentation tag that can contain nested presentation tags and persistent logic tags inside it.

Presentation tag

A tag that creates visible or interactive content in the document and remains in the document as part of its structure.

Primary field

The main field of a tag. It is the field that usually carries the tag's main content (i.e. value(s) assigned directly to the tag itself) when no field name within the tag is specified. Different tags use the default field in different ways.

Scalar field

A field that contains a single value.

Tag

Tags are instructions or object definitions in ioL that may create objects, perform actions, or generate values. Tags are generally enclosed in angle brackets < > to differentiate them from regular output. The angle brackets may also enclose field initialisers, primary field values, and an object name if present. In some syntactic cases where there is no ambiguity, the angle brackets are not required.

Transient logic tag

A tag that performs an operation but does not remain in the document after it is evaluated. It may still generate one or more values corresponding to the result of the operation.

Value

A piece of data. A value may be a single number, a string of text (zero or more characters), a reference to an object, or one of the following special values: null, true, false, inf, invalid.

Vector field

A field that contains a list of values.